Sophie_M has given you some excellent practical advice, 1800REPECT is exactly right, as are the other references.
I read your post -a brave thing to do, and one that shows how stuck you are. I wanted to say a couple of thngs.
They may not mean much when you are upset and can hear your mum crying but please re-read this and think on it in quieter times.
First you are not " ruining any thing more". Your assaults were serious injuries to you, and like any serious injury they have to receive proper treatment. You have taken the first step, to tell your parents. Hopefully this will be followed by proper medical treatment.
No, it is not easy, and your mum being upset is natural, don't take what she said or seeking quiet alone in the bathroom as anything other that an expression of love and grief on your behalf, the words do not matter. Every one handles hardship and hurt in different ways, that is simply you mother's. You are not killing her or making things worse, you are simply going to the adult who takes care of you and asking for care. Yes it hurts you to hear her cry, as I said it is the right path but not easy at all for you.
The thing that can be hard to remember is that it is the people that abused you who created all this grief and injury. You have borne it for longer than most and now need to admit you need help and support. That's good!
Please call 1800RESPECT and start to get adults on your side who can advise and help
You can always come here, we do care about you